Query on data billing

On the 6th of September 2015 I downloaded some app that I thought it was for free. Later on I realized my cellphone has been soft locked. On enquiry with Vodacom I was advised that my data usage was beyond my limit. The lady on the phone informed me that I have used data to the value of R7800.00. I painfully accepted my ignorance here that costed me so much. Anyway on 7th October I wanted to part pay an amount of R5000 on the account. I called Vodacom just to double check. To my surprise Keletso Ntunya informed me that my balance is over R10000! I insisted that she listens to the tape of 6th September to hear that I was informed of R7800 bill. She agreed to it and advised that on the same day she will get back to me. Since that day I have not received any feedback except by own follow up calls to Vodacom for feedback which I have not received to date. On the 15th Vodacom deducted the outstanding balance of R5241 after deducting the R5k I paid on the 7th. I have since I instructed my bank to reverse this payment until I hear from Vodacom on my request. All I request is for Vodacom Supervisor to listen to the recording of my call on 6th Sep 2015.